class Solution {
    public boolean wordBreak(String s, List<String> wordDict) {
        boolean[] valid=new boolean[s.length()+1];
        valid[0]=true;
        for(int i=1;i<=s.length();i++){
            for(int j=0;j<i;j++){
                if(wordDict.contains(s.substring(j,i))&&valid[j]){
                    valid[i]=true;
                }
            }
        }
        return valid[s.length()];
    }
}